Joe Pucci, right, a conceal carry advocate and Virginia Tech freshman, talks with no guns on campus opponents during a Virginia Citizens Defense League rally and counter-demonstration on the Virginia Tech campus in Blacksburg, Va.

WASHINGTON — The US Supreme Court declined Monday to take up a potentially important gun rights case examining whether a federal regulation banning loaded firearms from vehicles in a government park violated the constitutional right to keep and bear arms.

Lawyers for a Virginia man had asked the justices to examine a question left largely unresolved in the high court’s two prior landmark rulings identifying the scope and substance of Second Amendment protections. The question is: Does the Second Amendment guarantee a right to bear arms in public for personal protection?

The court dismissed the case in a one-line order without comment. The action leaves lower court rulings intact and postpones the prospect of high court clarification on a key gun rights issue.

In 2008, the Supreme Court ruled that the Second Amendment establishes a fundamental right of law-abiding individuals to keep a handgun in their home for self-protection. In 2010, the high court extended that ruling to apply Second Amendment guarantees beyond federal enclaves like Washington, D.C., to all state and local jurisdictions.

The dismissed appeal, Masciandaro v. US (10-11212), had asked the court to examine whether Americans have a right to carry loaded weapons in public places for self defense.

How the justices answered that question would have established guideposts for future gun regulations at the local, state, and national levels of government.

In the 2008 decision, District of Columbia v. Heller, the court said that gun rights are not unlimited. The court said there is no right to “carry any weapon whatsoever in any manner whatsoever and for whatever purpose.”

Gun rights advocates say that statement confirms a right to carry at least some weapons, in some manner, for some purpose.

The high court also said that “laws forbidding the carrying of firearms in sensitive places” would not necessarily violate the Constitution. Gun rights advocates counter that the statement, again, suggests that a right to carry firearms must therefore exist in non-sensitive places.

The rejected appeal stemed from the June 2008 arrest of Sean Masciandaro for carrying a loaded handgun in his car on national park land. Mr. Masciandaro and his girlfriend were sleeping in his car which was parked improperly in a lot on park land along the Potomac River near Alexandria, Va.

A US Park Police officer woke Mr. Masciandaro by tapping on the window. When Masciandaro produced his driver’s license, the officer noticed a large knife protruding from under the front seat. The officer asked Masciandaro if he had any other weapons. When he answered that he also had a loaded handgun, the officer placed Masciandaro under arrest.

Masciandaro said he often slept in his car while traveling on business and that he kept the gun for self-defense. The park where he was arrested was only 20 miles from his home in Woodbridge, Va.

Masciandaro was convicted of violating the federal regulation, and fined $150.

While his appeal was pending, the government changed its regulation, allowing the carrying of loaded firearms on federal land whenever that conduct is permitted under state law. In addition, three weeks after his arrest, the Supreme Court issued its decision in the Heller case.

A panel of the Fourth US Circuit Court of Appeals affirmed Masciandaro’s conviction, ruling that he had violated the law as it existed at the time of his offense.

The appeals court also ruled that the federal ban on loaded firearms in vehicles on park land was a reasonable regulation within the government’s power to enact and enforce

Two of the three judges declined to address the underlying issue of whether the Second Amendment protects a right to carry loaded firearms in public for self defense. “We think it prudent to await direction from the court itself,” Circuit Judge J. Harvie Wilkinson wrote.

“There may or may not be a Second Amendment right in some places beyond the home, but we have no idea what those places are, what the criteria for selecting them should be, what sliding scales of scrutiny might apply to them,” he said. “The whole matter strikes us as a vast terra incognita that courts should enter only upon necessity and only then by small degree.”

Judge Wilkinson mentioned an additional reason for his reluctance to wade into the controversial issue. “This is serious business. We do not wish to be even minutely responsible for some unspeakably tragic act of mayhem because in the peace of our judicial chambers we miscalculated as to Second Amendment rights.”

He added: “It is not far-fetched to think the Heller court wished to leave open the possibility that such a danger would rise exponentially as one moved the right from the home to the public square.”

Gun rights advocates at the Second Amendment Foundation filed a friend of the court brief challenging Judge Wilkinson’s perspective on the issue.

“No court should wish to feel responsible for a violent crime that could have been averted or disrupted had the court not ‘miscalculated as to Second Amendment rights’ and left the victim without arms for her defense,” Alan Gura wrote in a brief urging the high court to take up the case.

In urging the Supreme Court not to take up the Masciandaro case, US Solicitor General Donald Verrilli said the government’s substantial interest in promoting public safety justifies the federal ban on loaded weapons on federal land.

“The decision of the court of appeals does not conflict with any decision of this court, any federal court of appeals, or any state court of last resort,” Mr. Verrilli wrote in his brief to the court on behalf of the Obama administration.

Masciandaro’s lawyer, Assistant Federal Public Defender Rachel Martin countered in her own brief that the high court should act now. “This case gives the court the opportunity to expressly hold what it already decided in Heller: the right to keep and bear arms includes the right for a law-abiding citizen to do so in self-defense, and not just in the home,” she wrote in her brief.